I'd definitely bring gloves- June in Charleston still has a really good sea breeze that kicks in sometime around noon-1 pm, and hauling quickly on a line repeatedly can cause some wear spots on your hands. I raced bikes for years and rarely wore gloves (except for the occasional criterium), but I do for this sport! If you forget, there are decent cheapies available at West Marine just across the Ashley River from the downtown area. You should not need real foul weather clothing, though- if anything, something for light rain and that's about it. We've been sailing in shorts occasionally this winter, and hopefully, this will be the last week of full-foulies... My wife will wear full foulies pretty much all year long, but when it rains, she melts! It's also very sunny here, so I'd bring a hat with lanyard. Hope that helps?